Furnace construction



Dec. 30, 1930. H. DAUM 1,786,829

FURNACE CONSTRUCTI ON Filed July '10, 1928 3 nve'n fo'b Ham" 9 pa um Patented Dec. .39, 1930 I omen STATES HARRY DAUM, or PITTSBURGH, rnnNsYLvAnIA FURNACE CONSTRUCTION Application filed July 10, 1928. Serial No. 291,560.

This invention, which relates to an improvement in the construction ofv melting furnaces and more particularly to an 1111- provement inthe construction of open'hearth furnaces, has for its object to provide a new type of bulkhead in furnaces of the character referred to, especially adapted to greatly 1ncrease the life of such bulkheads and to eliminate the large repair costs occasioned by the type of bulkheads now in use. 7

7 Another object of my invention is to provide bulkhead construction which will entirely dispense with the laborious task vof making hot repairs, as is now done with the V ordinary type of bulkhead.

A further object of my invention is to provide a bulkhead construction of such character that the products of combustion Wlll be conducted from the furnace in such a manner as to so temper the bricks in the bulkhead that it will be almost impossible to burn them away; p y

In setting forth the improved detallsof construction of my bulkhead, the purpose of my invention will bebest understood by referring-to the conditionswliich exist everywhere withthe bulkheads. as they are built at present. p V

In the operation of any open hearth furnace, the products of combustion. after passing across the hearth, are conducted across a bridge wall into downtakes or ports, then to the regenerative chambers and thence to the stack. i r

As there are ports at either end of the hearth, it is customary at stated intervals to reverse the path of travel of the products of combustion to the stack; that is to-saythat for a period of from fifteen to twenty min- 40 utes the products of combustion will be conducted to the stack through the ports of one end of the furnace, and then for an equal period of time they will Y be conducted through the ports in the opposite end of the furu ace.

' That part of the furnace wall which forms the end of the furnace and which also is the outerend wall of the port, or downtake is known as the bulkhead. The bulkhead is I built of a highly refractory material, usually silica brick. The products of combustion as they pass'over first the melting charge and later the liquid slag, pick up and carry with them finely divided particles of iron oxide, lime, andother chemical compounds.

The three major causes of the short life of bulkheads are: (1) the extreme high tem perature of the outgoing products of combustion, (2) their velocity, and (3) the slagging of the bricks caused by their reacting with the chemical compounds carried over by the combustion products.

The combined action of these three conditions cause most bulkheads to wear through on from fifty to seventy-five heats, whereas the remainder of the furnace is good for from three hundred to six hundred heats, depending on the type of furnace and the grade of steel being made.

One method being used to hold the bulkheads in place is the installation of costly water-cooled equipment. This requires a heavy outlay of money, and means that thousands of gallons of water must be used every day, and when a leak occurs, the efficiency. of the furnace is greatly decreased.

Buteven with thewater-cooled equipment the bulkheads burn away and when the bricks are only two or three inches thick, the chilling et'fect 'of the cooling water is so great that the entering gases become chilled and the fuel consumption of the furnace is greatly increased. Finally, the gases become so much affected by the water that the furnace must beshut down to rebuild the bulkhead. My

invention makes it possible to eliminate all this expensive equipment and to dispense with all water about the bulkhead.

These and other objects I attain by the construction shown in the accompanying drawing, wherein for the purpose of illustration is shown a preferred embodiment of my invention and wherein Figure 1 is a section on the line 1-1 of Figurefl; v

F igure2 is a verticallongitudinal section of the port end of an open hearth furnace;

Figure 3 is a section on the line 33 of Figure 1.

Beferringnow more particularly to the,

drawing, the numeral 10 indicates the usual or ordinary bulkhead of an open hearth furnace. I place in advance of this bulkhead another wall or bulkhead 11 which parallels the bulkhead 10 in spaced relation thereto, so that between the bulkheads, a passage 12 is formed. Extending through this passage are preferably disposed tie elements 13 which may conveniently be formed by bricks, the ends of which form a portion of each of the walls. The passage 12 at its lower end communicates with downtakes 14 of the hearth which are preferably located in advance of the wall 11.

In the operation of a furnace with a bulkhead of this character, the outgoing products of combustion come into contact with the wall 11 and a portion thereof deflected downwardly to pass through the downtakes 14. The remainder of the combustion products pass through the openings 15 formed in the wall 11 to the space 12 and pass downwardly in this space to the downtakes, where they join that portion of the gases which has been deflected by the wall 11. This wall 11 is thoroughly honeycombed with the openings 15, so that a goodly portion of the products of combustion will pass to the downtakes through the passage 12." It will at once be obvious that by splitting the gases in the manner just described their action upon the bulkhead 10 is materially relieved, but at the same time the bulkhead 10 is being thoroughly tempered. Now when the wall 11 has been destroyed, the bulkhead 10 has become so well glazed that it is practically immune to any further action of the combustion products, so that a bulkhead that will endure throughout the furnace campaign is attained.

The temperatures in the vicinity of the bulkheads are usually from perhaps 2700 F. to about 3000 F so that bricks containing silica, chrome, magnesite, etc., will become vitrified. or glazed by the heat of the bypassed gases, and before the temporary or bafile wall has become worn away by'the main stream of hot gases. \Vhile the temporary wall 11 may contain silica or other vitrifying material, it is worn away so rapidly thatordinarily no protecting glaze is formed thereon.

Since the construction hereinbefore set forth is capable of a certain range of change and modification without materially departing from the spirit of the invention, I do not limit myself to such specific structure except as hereinafter claimed.

I claim 1. The step in the making of furnaces, which comprises installing a wall containing .vitrifiable material, and placing a temporary wall in position to deflect a portion only of the gases from contact with the first-named wall, the temporary wall being of such character that it will not be destroyed by the said gases until after a glaze has formed on the first-named wall.

2-. In a regenerative furnace, downtakes, a main bulkhead wall adjacent the downtakes and a relatively short-lived false bulkhead arranged inwardly of the bulkhead wall and spaced therefronr to provide therebetween a downwaidly-extending passage the lower end of which is in communication with the downtakes, the false bulkhead having openings permitting the passage of gases to said space and the main bulkhead wall containing vitrifiable material.

3. In a regenerative furnace and in combination with the bulkhead thereof, a relatively short-lived baffle arranged in advance of the bulkhead and directing a portion of the gases downwardly before'they come into contact with said bulkhead and downtakes conducting gases deflected downwardly by said 'bafile and by the bulkhead from the furnace, the said bulkhead containing vitrifiable material.

4. In a regenerative furnace, a bulkhead containing vitrifiable material, a relatively short-lived perforated wall opposing the bulkhead in spaced relation thereto and tied to the bulkhead and downtakes communicating with the space between the bulkhead and wall and adapted to receive gases deflected by said wall.

5. In a regenerative furnace, downtakes, a bulkhead wall adjacent the downtakes and containing vitrifiable material, and a relatively short-lived false bulkhead arranged inwardly of the bulkhead wall and spaced therefrom to provide therebetween a downwardly-extending passage the lower end of which is in communication with the downtakes, the false bulkhead having openings permitting the passage of gases to said space, and means connecting the bulkhead and false bulkhead and forming a portion of each thereof.

6. In a regenerative furnace and in combination, downtakes, a bulkhead containing vitrifiable material for directing gases to said downtakes, and temporary means inadvance of the bulkhead deflecting a portion of the gases to said downtakes and preventing direct contact of said portion of gases with the bulkhead wall.

In testimony whereof I hereunto aflix my signature.

HARRY DAUM. 

